The present invention relates broadly to a breathing exercise device, and more specifically to an incentive spirometer for use by post-operative patients to encourage them to resume normal deep breathing. The purpose of the device is to provide motivation for the patient to make a maximum inspiratory effort and to furnish visual and/or audio feedback to show the patient how well he achieves the goals set for him.
The medical literature indicates that significant pulmonary complications occur in from 20-40% of patients following abdominal or thoracic surgery. The best evidence seems to suggest that the cause is an abnormal pattern of ventilation. Normally, a patient takes spontaneous deep breaths every five to ten minutes. This assists in achieving maximal inflation of the alveoli. If the pattern changes to a shallow, monotonous tidal ventilation, gradual alveolar collapse can occur within one hour. After several hours without such deep breathing, gross atelectasis will occur. Many post-operative patients have this shallow breathing pattern due to their generally weakened condition accompanied by pain from the incision and from the sutures.
In order to prevent or to correct the atelectasis, respiratory maneuvers must be instituted which emphasize maximal alveolar inflation as well as the maintenance of a normal functional residual capacity.
There are three basic techniques employed today to encourage deep breathing and maximal alveolar inflation. Intermittent positive pressure breathing, commonly known as IPPB, has been widely used in intensive care units of hospitals to treat and prevent atelectasis by dilating collapsed bronchi and expanding unventilated alveoli by exerting a positive pressure through the airway. The routine use of the intermittent positive pressure breathing equipment has recently come under heavy criticism and many hospitals are searching for alternative methods of treatment. Among the disadvantages of IPPB is the considerable expense of this treatment for the patient.
A technique which is now used with increasing frequency is spontaneous breathing with coaching which many feel is the ideal method because it is the closest to normal. A problem with this method is that it requires a considerable amount of time on the part of a respiratory therapist.
Incentive spirometers have been developed and these devices are used for the correction and prevention of inadequate ventilation of the alveoli due primarily to the shallow pattern of breathing following surgery as noted above. These devices have been designed to encourage patients to breathe when they might otherwise suppress their normal breathing due to pain from their incisions. Incentive spirometers are now enjoying a growing amount of popularity as an alternative to IPPB. The use of such devices is much less costly for the patient and there are fewer contraindications. If the technique is explained and taught properly to the patient by the therapist, incentive spirometers will require much less of the therapist's time since the patient can perform the breathing exercise activity on his own. The basic idea is to encourage the patient to make a prolonged inspiratory effort which he might otherwise suppress.
There are two distinct types of spirometer devices available in the market today. The first type is a simple disposable device, comparatively inexpensive, and is known as a "blow bottle." With blow bottles, the emphasis is on expiration which is exactly the opposite of what is desired. Whatever inspiration exercise obtained with these devices is achieved by the inspiration necessary for the patient to subsequently exhale. The problem present is that only a minimal expiration is required, thus making a maximal inspiration unnecessary. Accordingly, blow bottles do not meet the requirements of a good incentive device for the prevention or treatment of atelectasis, and in fact they may accomplish the opposite of what is desired.
The other type of incentive device presently available in the market is considerably more complex and expensive. These devices have some advantages over the blow bottles in the way in which they measure the number of efforts and volume achieved. There are disadvantages, however, the principal one being the initial high price and their bulky size which makes them difficult to handle. Many respiratory therapists consider these devices to be unnecessarily complicated and expensive.